Computer add-on card capable of outputting different type of digital TV signals

ABSTRACT

This invention is about a computer add-on card that is capable of transferring MPEG-2 Transport Stream file from a computer storage (hard disk, DVD-ROM, etc.) to an external equipment such as: Digital TV settop box, modulator, etc. Besides handling PCI protocol communication, this add-on card also controls MPEG-2 Transport Stream generation, and signal format and interface conversion. To incorporate various output signal formats and interfaces, a daughter board is implemented as the output signal format and interface converter part. Using this daughter board, user can have various different Digital TV output signals without the need of modifying the application program.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The presented invention relates to computer add-on cards, particularlyto a computer add-on card that is capable of outputting variousdifferent type of digital TV signals depending on user configuration.

2. Description of Related Art

Digital TV has recently become the focus of the next generationentertainment and information service in the broadcast environment. Manyinstitutions and standard bodies have published different Digital TVstandards with different signal formats (PECL, LVDS, RS-422, etc.) andinterfaces (204-Byte parallel mode, serial, etc.) based on MotionPicture Experts Group-2 (MPEG-2) standard. Each Digital TV standard hasits own application and market segment.

To cope with this situation, a testing tool—such as MPEG-2 TransportStream generator—with various signal format and interface support is animportant key to the digital TV related products development.Conventionally, this kind of testing tool is very expensive and onlyprovides some limited number of output formats. If user needs anotheroutput signal format and interface, he has to spend more money topurchase a signal converter or even a new module from the originalmanufacturer. In the worst case user will have to purchase it fromanother testing tools manufacturer if the original manufacturer does notsupport this signal format. Again because these testing tools are notcompatible one another, user must purchase a whole new testing tool setfrom the other manufacturer and abandon the old one that has exactly thesame functions except the different output signal and interface. Fromthe user's view point, it is quite a waste of resources. The moreDigital TV standards they adopt in your products, the more waste theymake to purchase these testing tools. Therefore, to improve thiscondition users need a low cost and easy to implement testing tool thatis capable of outputting different signal formats and interfaces.

SUMMARY OF THE INVENTION

The main purpose of the presented invention is to provide a low cost PCIbased add-on card that is capable of transmitting various Digital TVsignal formats depending on user's requirement. This add-on cardcomprises the following components:

An interface daughter board for converting the output signal format.

A Peripheral Component Interconnect (PCI) bus interface that connects tocomputer's PCI slot.

A PCI Bridge to handle communication between computer host and thisadd-on card.

A Field Programmable Gate Array (FPGA) unit that provides control signalconversion.

A bit rate generator that produces all the clock signals needed by thesystem.

Two First In First Out (FIFO) buffers that function as temporary datastorage.

An output connector where various DTV signal formats are output from.

Using this flexible design architecture, it is very easy to integrateany Digital TV signal formats and interfaces to this testing tool. Tohave different output interface, all the user needs to do is replacingthe daughter board on this add-on card with the new different one andsetting the appropriate control jumper position. The user does not needto change anything else, including the application program, andeverything will work properly.

The other purposes, advantages, and features of this invention willbecome more apparent from the following detailed description and theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows the system block diagram of this invention.

FIG. 2 shows the block diagram of the interface daughter board of thisinvention.

FIG. 3 shows the control jumper of this invention.

FIG. 4 shows the connection between this invention and an externalequipment for DVB LVDS interface.

FIG. 5 shows the location of various connectors and control jumper ofthe add-on card of this invention.

FIG. 6 shows the interface daughter board of this invention.

FIG. 7 shows 204-Byte parallel mode timing diagram of this invention.

FIG. 8 shows 188-Byte parallel mode timing diagram of this invention.

FIG. 9 shows serial mode timing diagram of this invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

FIG. 1 shows a system block diagram of a computer add-on card that iscapable of outputting various different type of Digital TV signals inaccordance with this invention. The add-on card comprises a PCI businterface 11, a PCI bridge 12, a FPGA unit 13, a bit rate generator 14,a set of FIFO buffers 15, an interface daughter board 16, and an outputconnector 17. Besides handling PCI protocol communication, this add-oncard also controls MPEG-2 Transport Stream generation, and signal formatand interface conversion.

The connection between this add-on card and computer is made through PCIbus interface 11. All PCI protocol communication is handled by PCIbridge 12. The data received from computer through PCI bus are then sentto FIFO buffers 15. These FIFO buffers 15 consist of a Least SignificantBit (LSB) buffer 151 and a Most Significant Bit (MSB) buffer 152 used astemporary LSB and MSB data storage respectively before these data arefurther sent to interface daughter board 16 for signal format andinterface conversion. The FPGA unit 13 is responsible for providingcontrol signals conversion. To provide all clock signals needed by thesystem, a bit rate generator 14 is used.

The interface daughter board 16 functions as interface and signal formatconverter for the add-on card. The signals input coming from the add-oncard to the interface daughter board will be translated into itscorresponding signals by the signal translator module before being sentback to the add-on card. Changing the definition of the output connectorof the interface daughter board will change the interface definition ofthe add-on card's output. This invention enables user to incorporatedifferent output signal formats and interfaces to the add-on card byreplacing the interface daughter board. FIG. 2 shows the block diagramof the interface daughter board.

To facilitate the interface daughter board hardware configuration, an8-pin control jumper located on the add-on card is, as shown in FIG. 3,is used. The configuration of this control jumper is as follows:

1-2 is fitted: parallel output data format is enabled.

1-2 is not fitted: serial output data format is enabled.

6-8 is fitted: output SYNC signal is enabled.

4-6 is fitted: output SYNC signal is always low.

3-5 is fitted: output positive edge triggered CLK signal

5-7 is fitted: output negative edge triggered CLK signal

FIG. 4 shows the connection between the add-on card and an externalequipment for Digital Video Broadcasting Low Voltage DifferentialSignaling (DVB LVDS) interface. In this case the connection should bemade by using a 100 Ohm, 24 Gauge, 12 twisted pairs with overall shieldcable. The maximum cable length is 30 feet. For the other Digital TVsignal interfaces, suitable cable will be needed for the connection.

The add-on card and the interface daughter board are shown in FIG. 5 andFIG. 6 respectively. The signals from the add-on card are sent to theinterface daughter board through the first interface port (TSC Port A52). On receiving these signals, interface daughter board 16 will do thenecessary signal and interface conversion and send the converted signalsback to the add-on card through the second interface port (TSC Port B51). These signals are then output to the external equipment through theoutput connector 17 of the add-on card.

The first interface port and the second interface port should bedesigned to be different to prevent the user from misplacing theinterface daughter board 16 to the add-on card that can causes permanentdevice damage. Some approach to this is to use two connectors withdifferent pin number or two different type connectors for the first andsecond interface ports. For example, TSC Port A has 24 pins, while TSCPort B has 26 pins. Please refer to FIG. 5 and FIG. 6 for betterunderstanding. The pin assignments of TSC Port A are as follows:

Pins 1, 3, and 5: 5 V power source.

Pins 2, 4, 6, 8, 10, 12, 14, and 16: DATA (0-7) signals.

Pins 7, 11, 15, 18, and 19: GND.

Pin 9: Data Valid (DVALID) signal.

Pin 13: Synchronization (SYNC) signal.

Pin 17: Clock (CLK) signal.

Pin 20: Serial Data signal.

Pin 21: Serial/Parallel control signal 0 (this signal is directlyconnected to the control jumper).

Pin 22: Serial/Parallel control signal 1 (this signal is directlyconnected to the control jumper).

Pins 23 and 24: 3.3 V power source.

In the description above, DATA (0-7) signals represent MPEG-2 TransportStream packet data word (8-bit data: DATA 0 to DATA 7) with DATA 7 asthe Most Significant Bit. As shown in FIG. 7 and FIG. 8, DATA (0-7)consist of 188 byte MPEG-2 Transport Stream packet in 188-Byte parallelmode. For 204-Byte parallel mode, these data also include 16 dummy bytespadded at the end of each MPEG-2 Transport Stream packet. To indicatethe valid bytes in a MPEG-2 Transport Stream packet, DVALID signal isused. Active logic “1” of this signal indicates valid data at theinterface.

External equipment can use SYNC signal to synchronize the data receivedfrom this add-on card. Active logic “1” usually indicates the beginningof a MPEG-2 Transport Stream packet. Some external equipment does notrequire this signal in 188-Byte parallel mode. Please also refer to thetiming diagram in FIG. 9 for signal relationship in serial mode of thisinvention.

The pin assignments of TSC Port B are as follows:

Pin 1 to pin 24: connected to pins 14, 1, 15, 2, 16, 3, 17, 4, 18, 5,19, 6, 20, 7, 21, 8,22, 9, 23, 10, 24, 11, 25, and 12 of the outputconnector respectively.

Pin 25: GND.

Pin 26: connected to pin 13 of the output connector.

The first interface port position forms an angle of 90 degrees withrespect to the second interface port position. Besides preventing theuser from misplacing the interface daughter board 16 to the add on card,this design also prevents the interface daughter board 16 fromloosening.

In conclusion, this invention provides a low cost, flexible, and easy toimplement testing tool for the development of Digital TV relatedproducts of any standards. Although the present invention has beenexplained in relation to its preferred embodiment, it is to beunderstood that many other possible modifications and variations can bemade without departing from the spirit and scope of the invention ashereinafter claimed.

What is claimed is:
 1. A computer add-on card that is capable ofoutputting various different types of Digital TV] signals, the add-oncard comprising: an interface daughter board for converting an outputsignal format; a Peripheral Component Interconnect (PCI) bus interfacethat connects to a PC's PCI slot; a PCI Bridge to handle communicationbetween a computer host and the add-on card; a Field Programmable GateArray (FPGA) unit that provides control signal conversion; a bit rategenerator that produces clock signals needed by the system; two First InFirst Out (FIFO) buffers that function as temporary data storage; anoutput connector where various Digital TV signal formats are outputfrom; and a control jumper to facilitate configuration of differentDigital TV formats and interfaces.
 2. The computer add-on card of claim1, wherein the FIFO buffers consist of a Least Significant Bit (LSB)buffer and a Most Significant Bit (MSB) buffer used as temporary LSB andMSB data storage respectively before they are further sent to interfacedaughter board for signal format and interface conversion.
 3. Thecomputer add-on card of claim 1, wherein the interface daughter boardinterfaces to the add-on card via a specific interface, and the signalsfrom the add-on card will be converted to another signal format andinterface by the signal translator on the interface daughter board andsent back to the add-on card for output.
 4. The computer add-on card ofclaim 3, wherein the interface daughter board supports various DigitalTV signal formats and interfaces conversion.
 5. The computer add-on cardof claim 3, wherein the interface daughter board receives its inputsignals from the add-on card through a first interface port and theconverted signals from the interface daughter board are sent back to theadd-on card through a second interface port.
 6. The computer add-on cardof claim 5, wherein the first interface port position forms an angle of90 degrees with respect to the second interface port position.
 7. Thecomputer add-on card of claim 1, wherein the standard PCI interface isused to connect it to computer.